1. Field of the Invention
The present invention relates to a water-based ink for ink-jet recording, an ink cartridge, an ink-jet recording apparatus and an ink-jet recording method.
2. Description of the Related Art
Regarding a water-based ink for ink-jet recording, it is important to suppress the increase in viscosity and solidification due to drying so as to realize stable discharge. For this purpose, a humectant (anti-drying agent) is generally used in the water-based ink for ink-jet recording. For example, there are proposed a water-based ink for ink-jet recording using glycerol as the humectant (see, for example, Japanese Patent Application Laid-open No. 2011-225759), and a water-based ink for ink-jet recording using diethylene glycol as the humectant (see, for example, Japanese Patent Application Laid-open No. 2006-96990 corresponding to United States Patent Application Publication No. US2006/0146108).
However, in the water-based ink for ink-jet recording using glycerol, the viscosity of glycerol is relatively high, and thus the effect for suppressing the increase in viscosity after the ink is dried (after drying) is not sufficient. On the other hand, in the water-based ink for ink-jet recording using diethylene glycol, although the viscosity of diethylene glycol is low, the diethylene glycol has a high volatility among the humectants, thus having such a problem that the diethylene glycol volatilizes due to drying. Therefore, any sufficient effect for suppressing the increase in viscosity after drying cannot be obtained. As described above, in both of the water-based ink for ink-jet recording using glycerol and the water-based ink for ink-jet recording using diethylene glycol, the effect for suppressing the increase in viscosity after drying is not sufficient. Accordingly, it is demanded that the increase in viscosity after drying is further suppressed in the water-based ink for ink-jet recording which uses glycerol or diethylene glycol.